From: Logan Gunthorpe <logang@deltatee.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
Linux MM <linux-mm@kvack.org>,
Stephen Bates <Stephen.Bates@pmcs.com>
Subject: Re: [PATCH v2 00/20] get_user_pages() for dax mappings
Date: Fri, 4 Dec 2015 18:58:36 -0700 [thread overview]
Message-ID: <566244CC.5080107@deltatee.com> (raw)
In-Reply-To: <CAPcyv4jjyzKgPMzdwms8xH-_RoKEGxRp1r4qxEcPYmPv7qStqw@mail.gmail.com>
Hey,
On 03/12/15 07:16 PM, Dan Williams wrote:
> I could loosen the restriction a bit to allow one unaligned mapping
> per section. However, if another mapping request came along that
> tried to map a free part of the section it would fail because the code
> depends on a "1 dev_pagemap per section" relationship. Seems an ok
> compromise to me...
Sure, that would work fine for us. I think it would be very unusual ;to
need to map two adjacent BARs in this way.
> Could you share the test setup for this one so I can try to reproduce?
> As far as I can see this looks like an ext4 internals issue.
Ok, well it's somewhat specialized and I can't run the failing test in a
VM because it requires infiniband hardware. We have a PCI card that has
a large memory backed BAR space. To use that with zone_device we have a
kernel patch that allows doing the zone device mapping with io memory
that has write combining enabled. Then we have an out of tree kernel
module that creates a block device from the PCI bar (similar to the pmem
code).
I could send you all of that, assuming you have a suitable PCI device.
However, I'm hoping none of the above has anything to do with the failure.
The test that is failing is a very simple RDMA test with an mmaped DAX
file. So hopefully it has nothing to do with the fact that a PCI device
backs it. So if you have some IB hardware available you could try our
simple test code from here:
https://github.com/sbates130272/io_peer_mem/tree/master/test
The server must be run with no arguments. Then the client can be run
with the address of the server as the first argument and a file that's
in a DAX fs (with a size greater than 4MB). The client and server should
be able to run on the same node, if necessary.
Let me know if this helps or if there's anything else I can provide. I
can probably dig into it some more on Monday on our setup.
Logan
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next prev parent reply other threads:[~2015-12-05 1:58 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-10 0:55 [PATCH v2 00/20] get_user_pages() for dax mappings Dan Williams
2015-10-10 0:55 ` [PATCH v2 01/20] block: generic request_queue reference counting Dan Williams
2015-10-11 12:59 ` Christoph Hellwig
2015-10-13 0:09 ` Dan Williams
2015-10-10 0:55 ` [PATCH v2 02/20] dax: increase granularity of dax_clear_blocks() operations Dan Williams
2015-10-10 0:55 ` [PATCH v2 03/20] block, dax: fix lifetime of in-kernel dax mappings with dax_map_atomic() Dan Williams
2015-10-10 0:55 ` [PATCH v2 04/20] mm: introduce __get_dev_pagemap() Dan Williams
2015-10-10 0:55 ` [PATCH v2 05/20] x86, mm: introduce vmem_altmap to augment vmemmap_populate() Dan Williams
2015-10-19 22:53 ` Williams, Dan J
2015-10-10 0:55 ` [PATCH v2 06/20] libnvdimm, pfn, pmem: allocate memmap array in persistent memory Dan Williams
2015-10-10 0:56 ` [PATCH v2 07/20] avr32: convert to asm-generic/memory_model.h Dan Williams
2015-10-10 0:56 ` [PATCH v2 08/20] hugetlb: fix compile error on tile Dan Williams
2015-10-10 0:56 ` [PATCH v2 09/20] frv: fix compiler warning from definition of __pmd() Dan Williams
2015-10-10 0:56 ` [PATCH v2 10/20] um: kill pfn_t Dan Williams
2015-10-10 0:56 ` [PATCH v2 11/20] kvm: rename pfn_t to kvm_pfn_t Dan Williams
2015-10-10 15:35 ` Christoffer Dall
2015-10-10 20:35 ` Paolo Bonzini
2015-10-10 20:57 ` Dan Williams
2015-10-12 12:51 ` Paolo Bonzini
2015-10-12 16:16 ` Dan Williams
2015-10-10 0:56 ` [PATCH v2 12/20] mips: fix PAGE_MASK definition Dan Williams
2015-10-10 0:56 ` [PATCH v2 13/20] mm, dax, pmem: introduce pfn_t Dan Williams
2015-10-10 0:56 ` [PATCH v2 14/20] mm, dax, gpu: convert vm_insert_mixed to pfn_t, introduce _PAGE_DEVMAP Dan Williams
2015-10-10 0:56 ` [PATCH v2 15/20] mm, dax: convert vmf_insert_pfn_pmd() to pfn_t Dan Williams
2015-10-10 0:56 ` [PATCH v2 16/20] list: introduce list_poison() and LIST_POISON3 Dan Williams
2015-10-10 0:56 ` [PATCH v2 17/20] mm, dax, pmem: introduce {get|put}_dev_pagemap() for dax-gup Dan Williams
2015-10-10 0:57 ` [PATCH v2 18/20] block: notify queue death confirmation Dan Williams
2015-10-10 0:57 ` [PATCH v2 19/20] mm, pmem: devm_memunmap_pages(), truncate and unmap ZONE_DEVICE pages Dan Williams
2015-10-10 0:57 ` [PATCH v2 20/20] mm, x86: get_user_pages() for dax mappings Dan Williams
2015-10-23 21:06 ` [PATCH v2 00/20] " Logan Gunthorpe
2015-11-30 22:15 ` Dan Williams
2015-12-02 22:02 ` Logan Gunthorpe
2015-12-02 22:04 ` Dan Williams
2015-12-04 2:16 ` Dan Williams
2015-12-05 1:58 ` Logan Gunthorpe [this message]
2015-12-08 0:00 ` Logan Gunthorpe
2015-12-08 0:48 ` Dan Williams
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